Universal bone screw screwdriver

ABSTRACT

The instant invention is directed to a universal bone screw screwdriver and in particular to a universal screwdriver that permits the removal of screws from bone plates that are manufactured by different manufacturers having distinct characteristics. The universal bone screw screwdriver comprises a handle that is adapted to removeably receive an elongated tool bit having a hollow center. The elongated tool bits correspond to the screw heads of different manufacturers. The universal bone screwdriver further comprises a torque limiting and locking spring to secure the elongated tool bit to the handle and inhibit over-tightening of the bone screw into the bone or bone plate as the case may be.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. patent applicationSer. No. 13/295,738 filed Nov. 12, 2011 and also claims priority to U.S.Provisional Patent Application No. 61/456,746 filed Nov. 12, 2010,entitled UNIVERSAL BONE SCREW SCREWDRIVER, the entire disclosure ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The embodiments of the present invention relate to a universal bonescrew screwdriver for use with interchangeable tool bits made bydifferent screw and bone plate manufacturers. More specifically, theinvention relates to a universal bone screw screwdriver that allows fora user to select the tool bit that is compatible with the screw that theuser is trying to manipulate and further can prevent the user fromover-tightening the screw in the bone or the bone plate.

Description of Related Art

Heretofore, use of bone screws and bone plates have become a significantaide in the treatment of bone fracture repair. There are numerousmanufacturers that supply the plates and bone screws to hospitals andother surgical centers to permit open reduction internal fixation.Although the efficacy of the bone plates and bone screws has beenestablished as a standard of care over many years, certain problems havearisen regarding the after care that may occur with respect thereto. Forexample, when a patient that has an open reduction internal fixationprocedure performed and is suddenly brought to an emergency room fortreatment, it is incumbent upon the hospital or treatment facility tohave an inventory of each of the screwdrivers necessary to remove eachcompany's particular screws. Because each company uses different typesof screws, it is not assured that the hospital or treatment facilitywill have the correct screwdriver. Further, even if the appropriatescrewdriver is available, it is not assured that that there will be timeto sterilize the screwdriver for several hours as is required byemergency room protocol.

Accordingly, a universal screwdriver that is suitable for use with thescrew heads of each manufacturer of screw and bone plates is desirable.

SUMMARY OF THE INVENTION

Generally speaking, in accordance with the invention, a universalscrewdriver capable of removing screws made by different bone screw andplate manufacturers is provided. A driver shaft is adapted to receiveinterchangeable tool bits that are suitable for use with the screw headsof different manufacturers. A recess is disposed in the driver shaft forreceiving a torque limiting spring which will secure the tool bit in theshaft. The torque limiting spring is removable and hence, permits thetool bit to be replaceably removed from the shaft and further, when thetool bit is disposed in the driver shaft the torque limiting springinhibits over tightening of the bone screws.

A second embodiment of the present invention comprises an elongated toolbit that is suitable to for use with the screw heads of differentmanufacturers. A recess is disposed along the handle for receiving atorque-limiting spring which will secure the elongated tool bit to thehandle. The torque limiting spring is removable and hence, permits theelongated tool bit to be replaceably removed from the handle andfurther, when in use, the torque limiting spring inhibits overtightening of the bone screws. The elongated tool bit may be hollow toallow the screwdriver to be used in conjunction with Kershner wires andcannulated screws.

Accordingly, an object of the instant invention is to provide animproved universal screwdriver for use with the bone screws of manycompanies.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing figures, which are merely illustrative, and wherein likereference characters denote similar elements throughout the severalviews:

FIG. 1 is a perspective view of the universal screwdriver constructedwith a preferred embodiment of an embodiment of the instant invention;

FIG. 2 is a perspective view of the driver shaft and tool bit interfaceconstructed in accordance with an embodiment of the instant invention;

FIG. 3 is an exploded view of the driver shaft, tool bit and torquelimiting spring constructed in accordance with an embodiment of theinstant invention;

FIG. 4 is an exploded view of the tool bit visible through the recess;

FIG. 5 is a sectional view of the driver shaft securing a tool bit usingthe torque limiting spring in accordance with an embodiment of theinstant invention;

FIG. 6 is a sectional view showing the manner in which the torquelimiting spring is connected to the driver shaft and is used to inhibitover-tightening of the screw in accordance with an embodiment of theinstant invention;

FIG. 7 is an elevational view of a torque limiting spring to be used inaccordance with an embodiment of the instant invention;

FIG. 8 is an exploded view of the driver shaft, tool bit and torquelimiting spring in the “lock position” constructed in accordance anembodiment of the instant invention;

FIG. 9 is an exploded view of the driver shaft, tool bit and torquelimiting spring in the “torque position” constructed in accordance anembodiment of the instant invention;

FIG. 10 is a perspective view of the universal screwdriver constructedas an embodiment of the instant invention; and

FIG. 11 is a cross-sectional view of universal screwdriver constructedas an embodiment of the instant invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT

Generally speaking, in accordance with the instant invention, auniversal screwdriver generally indicated as 10 in FIG. 1 is provided.In the embodiment depicted in FIGS. 1, 2 and 3, the universalscrewdriver includes a handle 12, a driver shaft 14, a tool bit 16, arecess 30 and a torque limiting spring 20. With specific references toFIGS. 2, 3 and 4, the tool bit illustrated therein is representative ofthe type of screws manufactured by numerous different companies, such asSynthes, Ostiomed, Villex, and Stryker as well as other orthopedicdevice manufacturers.

As illustrated in FIG. 2, the tool bit design will have a uniqueconfiguration such as a cruciform or hexagram or other types ofconfigurations and each manufacturer has a tool bit configuration thatis unique to the company. These tool bit configurations are designed tomate with a screw and hence, the screwdrivers provided by each companyare not suitable for use with the screws of another company.Accordingly, tool bit 16 illustrated in FIGS. 2, 3 and 4, is by way ofexample only, and is not limiting in any sense to the instant invention.

The driver shaft 14 is connected to the handle 12 as depicted in FIG. 1.One of ordinary skill in the art would appreciate the mechanism by whichthe driver shaft 14 is connected to the handle.

As illustrated in FIG. 3, a recess 30 is disposed on the driver shaft 14which can allow the inside of the driver shaft 14 to be externallyvisible. An elongated opening 22 extends through the driver shaft 14.The shank of the tool bit 16 has a uniformed cross-sectional dimensionand is adapted to be received in the opening 22. The shank of the toolbit is inserted into the opening 22 formed in driver shaft 14 and comesto rest at the thrust bearing surface 26 inside the driver shaft 14 asshown in FIG. 5. A slot 28, which includes a flat 29 (as shown in FIG.4), is provided in each of the tool bits and is brought into alignmentwith the recess 30 formed in the each shaft on the tool bit. When theshaft of the tool bit is inserted up, into and against the thrustbearing surface 26 so that the tool bit is brought into alignment withthe recess 30 in the driver shaft 14, a locking mechanism can beinserted to secure the tool bit within the driver shaft 14.

In one embodiment, the torque limiting spring 20 is the lockingmechanism to secure the tool bit into the driver shaft 14 as depicted inFIGS. 3 and 4. One of ordinary skill in the art would appreciate othermethods by which the tool bit can be locked into the driver shaft 14.

The preferred dimensions of the torque limiting spring are depicted inFIG. 7, but by no means is limiting in any sense to the instantinvention. When the slot 28 of the tool bit is brought into alignmentwith the recess 30, the torque limiting spring 20 is inserted in therecess 30 to secure the tool bit 16 into the driver shaft 14 and therebypreventing any actual displacement of the tool bit. Removal of thespring to permit replacement of the tool bit is provided by snapping thetorque limiting spring 20 on or off thereby permitting the tool bit tobe easily removed or attached.

Additionally, in this position, the torque limiting spring 20 will restagainst the flat 29 during each rotation of the handle 12 and willinhibit the over-tightening of the screw in the bone or in the plate asthe case may be. When the tool bit 16 is engaged with the screw, as theuser rotates the handle 12, the tool bit 16 will encounter resistancefrom turning the screw into the bone or bone plate. As torque is appliedto the bone screw, the torque limiting spring 20 will start to be liftedby the flat 29. When the torque applied to the bone screw reaches thepre-set torque value of the torque limiting spring 20, the torquelimiting spring 20 will become disengaged from the flat 29. At thispoint, the driver shaft 14 can continue to be rotated, but the tool bit16 will have ceased rotating, thus inhibiting a user fromover-tightening a screw into the bone or bone plate. The user can selectthe desired torque limitation by utilizing a torque limiting spring 20that conforms to the user's needs.

In one embodiment, the torque limiting spring 20 comprises a flat arm 21flexibly connected on one end to a semicircular arm 23 as depicted inFIG. 7. In another embodiment, the torque limiting spring 20 furthercomprises a notch 25 on the interior surface where the flat arm 23 isflexibly connected to the semicircular arm 25 as depicted in FIGS. 2, 4,and 6.

In another embodiment, a flush hole 24 may be disposed on the drivershaft 14. The flush hole 24 extends into the thrust bearing surface 26.When a flush hole 24 is provided, the thrust bearing surface 26 does notextend through the entire diameter of the driver shaft 14. Rather thethrust bearing surface 26 extends perpendicularly to the wall of thedriver shaft 14 such that the area behind the tool bit 16 is accessible.In this manner, the flush hole 24 permits the area that receives theshaft of the tool bit 16 to be easily autoclaved and cleaned and anybone debris can be removed between usages.

In another embodiment, with like numerals used to reference likeelements in the embodiments described above, a universal screwdrivergenerally indicated as 10′ in FIGS. 10-11 is provided. In the embodimentdepicted in FIGS. 10-11, the universal screwdriver includes a handle12′, an elongated tool bit 31, a recess 30′, and a torque limiting andlocking spring 20′. The elongated tool bit 31 is adapted to engage withinterchangeable bone screws. The elongated tool bit 31 can either becomposed of a single piece that extends into the handle as shown in FIG.11, or optionally composed of two separated pieces, a driver shaft 16and a tool bit 14, as shown in FIGS. 1-3. Multiple elongated tool bitsare provided, each having different tips to engage with differentconfigurations of bone screws.

A recess 30′ is disposed along the handle 12′ such that the inside ofthe handle is externally visible. An elongated opening 22′ extendsthrough the handle 12′. The elongated tool bit 31 is adapted to bereceived in the opening 22′. The elongated tool bit 31 is inserted intothe opening 22′ and comes to rest at the thrust bearing surface 26′inside the handle 12′ as shown in FIG. 11.

A slot 28′, which includes a flat surface 29′ (as shown in FIG. 11), isprovided in each of the elongated tool bits 31 and is brought intoalignment with the recess 30′ formed the handle 12′. The slot 28′ formedby the flat surface 29′ is axially positioned on the elongated tool bitso that when the elongated tool bit 31 is inserted up, into and inabutment to the thrust bearing surface 26′, slot 28′ of the elongatedtool bit 31 is brought into alignment with the recess 30′ in the handle12′. Thus, a spring 20′ can be inserted to secure the elongated tool bit31 within the handle 12′.

When the slot 28′ of the elongated tool bit 31 is brought into alignmentwith the recess 30′, the spring 20′ is inserted into the recess 30′ tosecure the elongated tool bit 31 into the handle 12′ and thereby preventany actual displacement of the elongated tool bit. Removal of the springto permit replacement of the elongated tool bit is provided by snappingthe spring 20′ on or off thereby permitting the elongated tool bit to beeasily removed and/or attached. It should be noted that the torquelimiting spring 20 can be used as an alternative to the spring 20′ inthis embodiment of the instant invention, without departing from thescope of the invention.

Additionally, in this position, the spring 20′ will rest against theflat surface 29′ during each rotation of the handle 12′. The spring 20′comprises at least a first arm having first and second opening (27 and28) and a flat arm 21′. The spring 20′ also comprises a notch 25′ wherethe first arm and the flat arm meet. A first opening 27 of the spring20′ is designed such that it will not disengage from the elongated toolbit 31, regardless of the amount of torque applied to the screwdriver.That is, the user can impart unrestricted torque to the universalscrewdriver in the “lock” position of the spring 20′ without spring 20′being displaced when used in the position as shown in FIG. 8.

The second opening 28 is designed such that the spring 20′ willdisengage from the elongated tool bit 31 after a sufficient amount oftorque is applied to the screwdriver 10′ in use. When the universalscrewdriver 10′ is assembled and the spring 20′ is positioned such thatthe second opening 28 engages the elongated tool bit 31 as shown in FIG.9, as the user applies torque to the screwdriver, the elongated tool bit31 will encounter resistance. When such resistance exceeds the pre-settorque value of the torque limited spring 20′, the spring 20′will becomedisengaged, and accordingly the screwdriver 10′ will no longer be ableto impart force on the elongated tool bit 31. Accordingly, the handle12′ can continue to be rotated, but the elongated tool bit 31 will haveceased rotating, thus inhibiting a user from over-tightening a screwinto the bone or bone plate. The user can select the desired torquelimitation by utilizing a spring 20′ that conforms to the user's needs.

In another embodiment, as shown in FIG. 11, the elongated tool bit 31may be hollow along the longitudinal axis in order to accept a Kershnerwire, or the like, along such longitudinal axis and create a continuouschannel with a cannulated screw.

It should be noted that the spring 20 or 20′ could be located at anyposition along the elongated tool bit 31 depicted in FIGS. 9-11 withoutdeparting from the scope of invention.

Thus, while there have been shown and described and pointed out novelfeatures of the present invention as applied to preferred embodimentsthereof, it will be understood that various omissions and substitutionsand changes in the form and details of the disclosed invention may bemade by those skilled in the art without departing from the spirit ofthe invention. It is the intention, therefore, to be limited only asindicated by the scope of the claims appended hereto.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed and all statements of the scope of the invention which, as amatter of language, might be said to fall there between. In particular,this invention should not be construed as being limited to thedimensions, proportions or arrangements disclosed herein.

What is claimed is:
 1. An orthopedic universal screwdriver comprising: a handle having a slot that is adapted to receive an elongated tool bit, wherein the elongated tool bit has a hollow center along a longitudinal axis; a recess disposed in said handle; and a torque limiting and locking spring comprising at least two arms, wherein the first arm is a flat arm and the second arm has at least two openings, wherein the torque limiting and locking spring is removeably attachable to the handle via said recess for securing the elongated tool bit in at least one of the openings to said handle.
 2. The orthopedic universal screwdriver of claim 1, wherein the torque limiting and locking spring is capable of preventing over tightening of a bone screw.
 3. The orthopedic universal screwdriver of claim 1, wherein the first arm comprises a first interior surface and the second arm comprises a second interior surface, and said torque limiting and locking spring further comprises a notch at a position where the first and second interior surfaces are joined together.
 4. The orthopedic universal screwdriver of claim 1 wherein a flat surface on the elongated tool bit and configured to align with the recess when said elongated tool bit is inserted into said handle and said torque limiting and locking spring being constructed to and positioned to engage the flat surface on the elongated tool bit. 